The present invention entails the transfer of inkjet printing images and/or textual information onto license plate substrates. Such license plate blanks cannot be fed into an inkjet printer, due to their stiffness, size, thickness and irregular surfaces containing embossed characters and peripheral ridges.
Only certain label materials can accept inkjet inks. Having pressure-sensitive backings, the labels are pasted onto objects. Some labels are sufficiently transparent so that the background"fades", leaving only the image visible. Such materials, however, are not acceptable for a "graphic" application and, thus, would not serve as a means to provide a license plate substrate with graphics and text. Additionally, a license plate window area is too large and the labels utilizing inkjet printing too small to satisfactorily jibe for a successful print job.
Images produced by means of inkjet printers may be transferred to other substrates by utilizing transfer or carrier sheets. Inkjet receptive layers (single or multiple) are coated onto a carrier sheet. The carrier sheet is first coated with a silicone release system, so that the inkjet layer(s) may be easily removed by pressure-sensitive adhesive or by heat and pressure. The inkjet layer(s) are sufficiently cohesive enough to be manually placed onto another substrate such as a license plate blank.
In the present invention an image produced by a computer is printed by an inkjet printer or an inkjet plotter. A treated transfer sheet material that will accept the image is placed in the media compartment of the printer or plotter. Once the printing is complete, the image disposed upon the carrier layer is easily removed from the backing of the transfer sheet material. The carrier sheet, bearing the graphics and text, is then adhered to a license plate blank.
The production of a transferable medium that will accommodate inkjet printing requires several elaborate steps, hereinafter enumerated:
1. On a dense, solvent hold-out paper, a coating of commercial silicone release is applied.
2. The solvent is removed from the paper, and the paper layer is then cured.
3. A carrier layer is coated onto the silicone release layer. This carrier layer is designed by this invention to have a greater cohesion than the adhesion to the silicone layer. A second characteristic of the carrier sheet is its ability to resist penetration of the inkjet ink. This ink resistance is necessary, so that the ink will not coat the silicone surface. The carrier must adhere to the silicone to allow for transport and manipulation which would otherwise be impaired by the penetrating ink. The carrier layer, however, must also be designed so that it is removable from the silicone layer (by peeling, for example).
4. A final coating is layered upon the upper surface of the carrier in order to receive the inkjet image. This layer is composed of resins/pigments to absorb and enhance the ink characteristics. This coating layer is designed by this invention to adhere well to the carrier layer.